MAPT and Alzheimer disease: PNFA is most commonly associated with the FTLD-tau pathologies of Pick's disease, corticobasal degeneration (CBD), and PSP.8 However, there is no simple one-to-one correlation, and other pathologies are also noted less frequently, including AD pathology.9 In comparison to the other PPA subtypes, LPA is most commonly associated with AD, rather than FTLD pathology, and can be considered as an atypical variant of AD.5,10